1. Field of the Invention
The present invention relates to an artificial knee joint used to properly restore knee joints significantly deformed by chronic rheumatism or osteo-arthritis, or those broken in traffic accidents or during disasters.
2. Prior Art
A conventional artificial knee joint replacement treatment is conducted by cutting the distal portion of the femur and the proximal portion of the tibia of a knee joint damaged or broken by disease or accident, and by inserting and securing a femoral component and a tibial component to the distal portion of the femur and the proximal portion of the tibia respectively so that the femoral component slides on the sliding surface of the tibial component, thereby allowing the knee joint to be bent.
When the femoral component of the artificial knee joint slides on the tibial component as described above to perform a knee bending movement, if the fermoral component 1 of the artificial knee joint rotates on the front upper surface of the tibial component 2 of the knee joint as shown in FIG. 5, the movable range of the femoral component 1 is limited, preventing a person with the artificial knee joint from taking a deep knee bending posture when sitting and thus causing inconvenience during his daily life. To solve this problem, a method has been taken wherein a post provided on the tibial component of an artificial knee joint controls the femoral component to ensure a bending movement between the femur and the tibia (for example, Japanese Laid-open Patent Application No. 63-132651). In the above-mentioned case of the method wherein the post provided on the tibial component controls the femoral component at the time of the bending of the artificial knee joint to securely offer a sufficient movable range to the artificial knee joint, the post receives all loads and undergoes stress concentration. The post is, therefore, deformed or broken and cannot attain desired functions.